The deadly H7N9 bird flu virus, that recently left at least 36 people dead in China, can infect ferrets and transmit from ferret-to-ferret via close contact and air-borne exposure, a new study warns today.
The report, released by Hong Kong experts, did not rule out the possibility of the human-isolated avian influenza A (H7N9) virus evolving further to form the basis of a future pandemic threat.
The research was published in the latest Science, the prestigious international scientific journal.
The study also finds that pigs can be infected by the H7N9 virus, leading to mild visible clinical signs and pneumonia, so the surveillance of pigs is needed to prevent the epidemic from spreading further.
To date, a total of 130 laboratory-confirmed cases of human infection with H7N9 virus have been reported on the Chinese mainland since March this year, causing 36 death. The case of "Family Cluster" in Shanghai and Shandong aroused concerns towards the potential risks of human-to-human transmission, state-run Xinhua news agency reported.
Guan Yi, professor of School of Public Health at HKU, said there is no "direct evidence" that has proved the virus can transmit from human-to-human.
"If the limited possibility of human-to-human transmission ranges on the scale of 1 to 10, I'd like to put it at one. It is very low."
However, the chance of H7N9 virus evolving further to form the basis of a future pandemic threat cannot be excluded, Guan said, adding public health measures should thereby be well maintained.
The H7N9 virus has the possibility to infect mammals, such as human, pigs and ferrets, the main mammal model for research into human influenza.
The research team, therefore, suggests that for better disease control and prevention, the health authorities should also take into consideration other poultry and pets which may have a chance to be contacted with the virus.
In addition, the infected animals do not necessarily develop fever and other related clinical signs, indicating that asymptomatic infections among human are possible.
Guan led the research team, in collaboration with the National Influenza Centre, Chinese Centre for Disease Control and Prevention, the Xinhua report said.
